[Menu] Fix menu for Safari browsers
[Menu] Fix menu for Safari browsers

Safari still to need the `-webkit-` prefix when using flexboxes.

OskarStark/EasyAdminBundle,alexgt9/EasyAdminBundle,ogizanagi/EasyAdminBundle,kamilZ/EasyAdminBundle,datagit/EasyAdminBundle,seydu/EasyAdminBundle,OskarStark/EasyAdminBundle,yceruto/EasyAdminBundle,kamilZ/EasyAdminBundle,thomasbeaujean/EasyAdminBundle,datagit/EasyAdminBundle,alexgt9/EasyAdminBundle,yceruto/EasyAdminBundle,thomasbeaujean/EasyAdminBundle,seydu/EasyAdminBundle,ogizanagi/EasyAdminBundle,ogizanagi/EasyAdminBundle,seydu/EasyAdminBundle,gabiudrescu/EasyAdminBundle,yceruto/EasyAdminBundle,datagit/EasyAdminBundle,gabiudrescu/EasyAdminBundle,thomasbeaujean/EasyAdminBundle,javiereguiluz/EasyAdminBundle,OskarStark/EasyAdminBundle,javiereguiluz/EasyAdminBundle,alexgt9/EasyAdminBundle,kamilZ/EasyAdminBundle,ogizanagi/EasyAdminBundle,gabiudrescu/EasyAdminBundle